Brake shoe key



Patented Feb. 8, 1938 -IKUNITED STATES PATENT OFFICE 7 Claims.

This invention relates to keys for connecting railwaybrake shoes tov brake heads of standard construction having cooperating lugs provided withopenings iorreceiving keys, and more par- 6( ticularly to keys of the general construction dis- 'closed in my Patents Nos. 2,026,324 and 2,051,909.

Itis among the objects of this invention to provide a brake shoe key of the type just referred to whichv has means for securely locking the Y: wedge in all of its arms-spreading positions,

which can be expanded sufficiently to accommodateitself to substantially all conditions of service, andwhich is exceptionally strong and du- .rable.. y The preferred embodiment of the invention is -illustrated in the' accompanying drawing in which Fig. 1 is a side view of my key inserted in the cooperating lugs of a brake head and shoe` but not locked therein; Fig. 2 is a side view showl ing thel key locked in place; Fig. 3 is a side view of the key locked in lugs that have become thin byv wear; and Fig. 4 is a face view of the key in reduced scale. n

Referring to the drawing, a brake shoe I hav- V ing Ya central lug 2 is shown associated with a brake head 3 provided with a pair of lugs 4 straddling lug 2. These parts are of standard construction. The brake shoe is connected to the brake head by a key extending through the three Y 3o, lugs and comprising a pair of resilient metal arms 6 and 'I connected to each other at their lower ends and spaced apart at their upper ends by an elongate wedge 8 having a tapered lower end. The upper ends of the arms are connected to- 35, gether with the wedge between them by a metal sleeve 9 engaged at its lower end by a short rib II on arm 1. To connect the lower ends of the arms together one of them is preferably provided with va tongue I2 that projects downwardly 40, through a hole I3 in theother arm. This type Vof lconnection is strong and inexpensive.

Theupper ends of the arms are turned outwardly as shown, the out-turned end of arm 'I forming a stop I4 for engaging the upper end of thebrake shoe to limit downward movement Vof the locking key when inserted in position. The upper end of arm 6 is bent outwardly slight- 1y ,to form a projection I6 which is adapted to be struck by a hammer to drive the key into place.

60 The upper endof wedge 8 is provided with an eye I'IA forming a head for driving the wedge into place and a loop through which a bar can be inserted Afor pulling'or driving the Wedge vout of place. ^The wedge is also provided with a detent v g55Y Ilfw-hich projects into the groove formed by rib of the arms apart.

(C1. iss-243) II and engages its upper end when the wedge is in its upper or outer position to limit outward movement of the wedge and prevent its removal from between the arms of the key.

To guide the wedge in its longitudinal move- 5 ment inwardly between the arms and thereby prevent its lower end from sliding out at an angle and not properly spreading the arms, the upper portion of arm 6 is provided in its inner surface with a longitudinal groove I9 in which there 10l slides a longitudinal rib 2I on the adjoining face of the wedge. Groove I9 is continued up to the top of arm 6 where it forms a corrugation that reinforces projection I6.

When wedge 8 is in its outer position the two 1.5V

arms are substantially in engagement for approximately the lower third of their length, as shown in Fig. 1, the remaining portion of arm 6 being offset relative to its lower part to permit the wedge to be disposed between the upper portions of the arms without spreading their lower portions apart.

Arm 'I is provided near its lower end with a downwardly tapered detent 22 which, in the inserted position of the locking key, preferably 25 lies just below the lower edge of the upper lug of the brake head. When the wedge is driven downwardly its lower end enters between the adjoining lower portions of the arms and spreads them outwardly with detent 22 disposed below the low- 30 er edge of upper lug 4, as shown in Figs. 2 and 3. Detent 22 thereby locks the key in the cooperating lugs of the brake head and shoe and prevents the accidental removal of the key therefrom.

A short distance from its lower end the wedge is provided with a portion 23 offset preferably toward arm l which in turn is offset at the lower end of rib II so as to receive oiset 23 and thereby prevent it from spreading the lower portion However, when the wedge is driven downwardly between the converging arms, offset 23 aids in spreading them apart, and is especially useful when the arms must be spread a considerable distance apart such as when the lugs have become worn, as in Fig. 3.

It is a feature of this invention that provision is made for locking wedge 8 in its inner or armsspreading position so that it can not work upwardly, due to the constant vibration and. flexing to which the key is subjected, and allow the arms to collapse. Accordingly, arm 'I between rib II and detent 22 is provided with a plurality of longitudinally spaced inwardly projecting detents 24, and wedge offset 23 is provided with one or 55 more depressions 25 for receiving any one of the detents 24. The engagement of these detents and depressions prevents the wedge from accidentally working out of its arms-spreading position and allowing the arms to collapse, but the wedge can be withdrawn when it is necessary to remove the key by striking eye 'l from below or by inserting a bar in the eye and pulling or striking the bar. An important advantage of locating the registering detents and depressions where just described is that the depressions do not weaken the wedge because they are pressed into the wedge and the ymetal displaced thereby on the opposite side of the wedge is disposed within offset 23 where it does not touch anything and therefore need not be filed off, which would decrease the cross sectional area of the wedge. Another advantage is that in case offset 23 is driven down past detents 24 and between the lower portions of the arms before the arms are spread far enough apart, as in Fig, 3, wedge detent I 3 engages detents 24 and locks the wedge in position.

It is another feature of this invention that as the wedge is driven downwardly between the lower portions of the arms it strikes a projectionr 21 on the inner face of arm 6 which forces arm 6 away from the wedge and thereby spreads the arms a distance greater th-an the thickness of the wedge. Likewise, the wedge is preferably provided with a projection 28 below offset 23 which is normally received by groove i9 in arm 6, but which engages the inwardly offset lower portion of arm 6 when the wedge is driven downwardly far enough. This increases the effective thickness of the wedge and thereby spreads the arms farther apart. If the wedge is driven in for its full length, its projection 28 will ride up on projection 2l and spread the two arms their maximum distance apart, as shown in Fig. 3. When the wedge is withdrawn from its arms-spreading position, projection 2l is received by the depression formed in arm 1 by outstruck detent 22, whereby the lower portions of the two arms are permitted to collapse into engagement with each other.

f A brake shoe key constructed in accordance with this invention is strong and durable because it is not weakened by the wedge-locking means which are effective regardless of the position of the wedge relative to the arms. This key is adapted to be used when the clearance afforded by the brake shoe and head lugs is small or great, because the key can be expanded from a relatively thin key to a relatively thick one.

According to the provisions of vthe patent statutes, I have explained the principle and mode of oper-ation of my invention, and have illustrated and described what I now consider to be its best embodiment.k However, I desire to have it understood that, Within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

l. A key for connecting a brake shoe to a brake head, comprisinga pair of arms connected to each other, and a wedge mounted between said arms and slidable longitudinally thereof for spreading them apart, said wedge having an offset portion intermediate its end portions provided in its outer surface with a depression, and the adjoining armr being provided with a detent for registering with said depression when said wedge is moved to armsspreading position., whereby withdrawal of the wedge is restrained.

2. A key for connecting a brake shoe to a brake head, comprisingl a pair of arms connected to each other, and a wedge mounted between said arms in engagement therewith and slidable longitudinally thereof for spreading them apart, said wedge having an offset portion intermediate its end portions provided in its outer surface with a depression, and the adjoining arm being provided with a plurality of longitudinally spaced detents for registering with said depression when said wedge is moved to arms-spreading position, whereby withdrawal of the Wedge is restrained.

3. A key for connecting a brake shoe to a brake head, comprising a pair of arms connected to each other, and a wedge mounted between said arms in engagement therewith and slidable longitudinally thereof for spreading them apart, said wedge having an offset portion intermediate its end portions provided in its outer surface with a depression, the adjoining arm being provided with a detent for registering with said depression when said wedge is driven inwardly to spread the arms, and said wedge being provided with a detent for engaging said arm detent when said offset portion is driven past the arm detent.

4. A key for connecting a brake shoe to a. brake head, comprising a pair of arms connected to each other, and a wedge mounted between said arms in engagement therewith and slidable longitudinally thereof for spreading them apart, said wedge having an offset portion intermediate its end portions provided in its outer surface with a depression, the adjoining arm being provided with a'detent for registering with said depression when said wedge is driven inwardly to spread the arms, said wedge being provided with a detent between its off-set portion and its outer end for engaging said arm detent when said offset portion is driven past the arm detent, and the outer portion of said adjoining arm being provided with a longitudinal groove for receiving said wedge detent whereby outer movement of the wedge is limited.

5. A key for connecting a brake shoe to a brake head, comprising a pair of arms connected to each other, a wedge disposed between the upper portions of the arms and adapted to be driven downwardly to spread the arms apart, said wedge having an offset portion spaced from its lower end and provided in its outer surface with a depression, the radjoining arm being provided with a detent for registering with said depression when the wedge is driven downwardly, and one of the arms having an inward projection adapted to be engaged by the' wedge when it isdriven downwardly.

6. A key for connecting a brake shoe to a brake head, comprising a pair of arms connected to each other, a wedge disposed between the upper portions of the arms and adapted to bey driven downwardly to spread the arms apart,`

said wedge having an offset portion spaced from its lower end and provided in its outer surface with a depression, the adjoining arm being provided with a detent for registering with said depression when the wedge is driven downwardly,

downwardly to spread the arms apart, the portion of one arm below the wedge being offset inwardly toward the other arm and provided with an inward projection, the opposite arm being provided in its inner surface with a depression receiving said projection and forming'on its outer surface a lug-engaging detent, said wedge having an oiset portion spaced from its lower end and provided in its outer surface with a depression, and the adjoining arm being provided with a plurality of longitudinally spaced detents for registering with said depression when the Wedge is driven downwardly to arms-spreading position.

- FREDERIC SCHAEFER. 

